


All Of You

by MeGaLoTrash



Category: Undertale (Video Game)
Genre: Anal Sex, Begging, Body Dysphoria, Body Worship, Ecto-Penis (Undertale), Ectobiology, Full ectobody, M/M, Mirror Sex, Overstimulation
Language: English
Status: Completed
Published: 2018-02-18
Updated: 2018-02-18
Packaged: 2019-03-20 20:08:37
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,835
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13725069
Author URL: https://archiveofourown.org/users/MeGaLoTrash/pseuds/MeGaLoTrash
Summary: Papyrus and his brother may be happy together and living on the surface, but there is one issue that he finds unbelievably puzzling.For Sinsandlustzone based on >>THIS<< amazing picture!See also: someawesome fanartof the mirror scene by @EzekielsSinbin





	All Of You

**Author's Note:**

  * For [AriSLzone](https://archiveofourown.org/users/AriSLzone/gifts).



Papyrus was Puzzled. 

It had nothing to do with the human word search he was currently working on during his enforced lunch break; the trivial clues were obviously no match for his superior intellect. Nor was it the reoccurring issue he had with the humans who frequented the shopping mall he was charged to protect confusing him with a decoration because of the time of year. That issue was frivolous and actually quite amusing on occasion. No, Papyrus’s positively perturbing puzzlement was over a much more ‘sensitive’ issue concerning his older brother. 

Their relationship may not be conventional; but since discovering their mutual attraction both he and Sans had thrived in the dual roles of brothers _and_ lovers. Despite their differences, Papyrus loved Sans more than anything in the whole world. Sans was kind and attentive, always wanting the best for other people. The bonus was him being blessed in the looks department, he had so many expressions that never failed to make Papyrus’s knees feel weak. The problem was that Sans didn’t see how amazing he really was, in fact Papyrus was pretty sure his brother felt the exact opposite. His self deprecating comments may have been hidden behind jokes and a sad smile, but Papyrus knew his brother well enough to seeing through the façade. 

What was puzzling Papyrus now though was why this issue seemed to be getting worse. They had been together almost 6 months, getting together around the same time that they moved to the surface. While Papyrus understood some of what Sans had been through, he didn’t understand why Sans thought so little of himself because of it. This affected every aspect of Sans’s life, but recently it had really been knocking the confidence he had in his own bones. Even though they shared a bed almost every single night, Sans being completely naked or exposed was something his brother rarely enjoyed. 

At first Papyrus thought that the confidence would come over time as Sans came out of his shell more. But last night Papyrus had asked if they could leave the lights on so he could shower his brother in affection Sans had frozen in fear. He hadn’t pressed the issue, more than happy to do anything to make Sans comfortable, but it had kept Papyrus up most of the night. Did Sans not understand that he loved him just the way he was? Papyrus was devastated that his previous efforts to make Sans feel good had fallen short of the mark. 

But there was no point in dwelling on his shortcomings when he could instead focus his energy on making it right. He would have to devise a plan; the perfect plot to help Sans understand just how much of an incredible skeleton he really was! Papyrus could barely contain his glee as he flipped out his emergency notebook and started to devise ways that they could spend the weekend together. He made sure to include some of Sans’s favourite things; a trip to Grillby’s new bar, napping, doing nothing. He also added in some more lewd activities he knew Sans enjoyed but was too shy to ask for. By the end of his break Papyrus was practically bursting at the seams with ideas, so much so that the rest of his shift he couldn’t help but jot down a few more when he had the chance. 

He couldn’t wait to surprise his brother, but more importantly, he really wanted to do anything he could to help! 

Papyrus tried to be as silent as a mouse when he returned home that night. He knew that Sans wouldn’t have minded being woken up when he came home, but Sans had been struggling with sleeping recently too, so Papyrus didn’t want to disturb him. Which was why he was completely surprised when he peeked through the door to their bedroom to find that Sans was awake. And not just awake, but standing in front of the mirror with his full body formed, nude bar his t-shirt and hoodie that he had pushed up and bunched under his arms. Papyrus slapped a hand over his mouth to silence his noise of surprise as he studied the scene in front of him intently. 

Sans was currently shifting himself from side to side, and studying his ecto-flesh in the mirror with a disgruntled look. He frowned and murmured something that Papyrus didn’t quite catch as he poked the swell of his formed stomach almost aggressively, like he was angry with himself for looking that way. Papyrus couldn’t understand what Sans’s problem was, he was practically salivating over his brother’s naked form. Papyrus loved the way Sans’s body looked; from the softness of his stomach, his thick thighs, and the impressive curve of his backside. Papyrus could feel his own magic hardening in his shorts as he caught a glimpse of Sans’s cock in the reflection of the mirror, but his soul felt conflicted considering how upset his brother seemed. 

He realised that one part of his plan needed to be moved forward immediately, but The Great Papyrus was not one to ever back down from a challenge! He could hardly hide his wicked grin as he pushed open the door.

“Hello Sans” Papyrus’s voice may have come out a little rougher than he planned it to, but then his obvious arousal was going to work in his favour.

Sans didn’t seem to notice though, he was far too preoccupied with the shock of being caught and scrambling to cover himself. “Pap! I didn't know you were back! I'm so sorry I'll get dressed and-”

“No Need Brother” Papyrus cut off his brother by coming up behind him, slowly pulling away his hands so he couldn’t cover himself up fully. “In Fact I’d Quite Enjoy Looking At You Some More”

“aw jeez, don’t say that pap” Sans replied with a defeated sigh, still trying to hide by curling in on  himself. “no one wants to see me when they could be looking at someone like you instead” 

Papyrus had to grit his teeth to stop himself from telling Sans just how ridiculous that statement was. Telling his brother he was wrong wasn’t going to help the situation because this was about how Sans felt. It didn't matter whether Papyrus disagreed, it was Sans's opinion of himself and that shouldn't be ignored, it would only make matters worse! But that didn’t mean he couldn’t show Sans exactly how he felt too, and maybe he could open his eyes to just how amazing Papyrus thought he was. Despite Sans’s squirming Papyrus gripped him tighter from behind, softly pressing his hardened magic against the curve of his brother’s ass. It took a lot of self restraint not to just pull his own pants off right now, but this kind of plan required the highest level of patience to work. 

Papyrus began to run his hands over his brother’s formed body, all of it, tracing the soft ecto-flesh even in areas he knew Sans was self conscious about. None of his murmurs of appreciation against Sans's skull were faked, in fact it felt good to finally show his appreciation for his brother’s whole body. He listened for the slight shift in Sans’s breathing and watched as his cock started to harden from the light stimulation. _Gods,_ he really was incredible. “I Think You're Beautiful”

Sans might have stopped squirming but hearing Papyrus’s voice had made his whole skull burn a bright blue “i’m not-ah!”

Hiding his smirk next to Sans’s skull, Papyrus cut him off by running one of his hands firmly over his brother’s ass “Let me finish Sans” Papyrus swatted one of his cheeks playfully, something that he knew was a secretly a huge turn on for his brother. “I Think You’re Amazing, But I Understand That You’re Struggling To See That Right Now. I Want To Show You Exactly How I Feel Though, If You’ll Let Me?”

Papyrus let the question hang in the air as he continued to run his hands over Sans lightly. He knew his brother was going to have to put a lot of trust into him for this, and he didn’t want to rush him. Sans was arching into his touches, his cock almost at full mast as his eye lights turned hazy. Papyrus had almost started to devise a backup plan where they could still have some fun when he heard the softest of agreements followed by Sans nodding his head vigorously. Papyrus would have loved to have heard how much his brother wanted this, but he reveled in the challenge of making Sans scream. 

Papyrus lead him over to their bed and pulled Sans into his lap in a similar position to how they had been stood. With this vantage point and his height advantage Papyrus could see _everything_ , including their reflection staring back at them from the mirror. Papyrus decided against pointing that little detail just yet, deciding instead to focus all of his attention on the skeleton in his lap. Papyrus kept his hands moving all over his brother’s body, the only parts being left untouched being the more lewd areas. Even if Sans was trying to entice him by wiggling himself into Papyrus's hands. That would all come later, the press of his still clothed cock firmly against Sans’s ass acting as a promise for more. 

Papyrus prided himself on being observant and a quick learner when he put his mind to it. He enjoyed being able to identify all of the spots Sans enjoyed being touched the most by the tell-tale hitch of his breathing. Papyrus was delighted to find out that the pseudo-flesh of his brother’s stomach was actually more sensitive than either of them had anticipated. He kissed the top of his brother’s skull, focusing most of his attention gliding his fingertips all over the swell of magic. Sans may have been hesitant at first over having a place he was insecure about touched so intimately, but within a few minutes he was starting to fall apart. His breathing was ragged, hisses of pleasure were escaping through his clenched teeth, and his cock was dribbling liquid magic freely. Papyrus wanted to point out how incredible Sans looked in their reflection, all wound up and ready to burst as he writhed in Papyrus’s lap, but it wasn’t time. _Yet._

Without meaning too Papyrus had started rocking up into his brother, even through the coarse material of his pants Sans’s ass was driving him crazy. It seemed like the right time to turn things up a notch so he briefly stopped touching Sans so he could wiggle his lower half out of its fabric prison. The moment the flesh of Sans’s ass made contact with his cock again Papyrus groaned and tried to stop his hips from bucking upwards. Sans just felt _so good_ and with the way he was now panting and moaning freely Papyrus could feel how much he needed it too. 

Papyrus knew that Sans wouldn’t need much preparation with how worked up he was already, but this whole plan was built upon drawing out their usual love-making sessions. So Papyrus deemed it completely necessary. He didn’t expect on of his hands to move on its own accord towards Sans’s open mouth, but he choked on his own moan when Sans ran his tongue all over the intruding digits. It took a little bit of manoeuvring, and sadly a loss of pressure against his own cock to move Sans forward enough so Papyrus could push his fingers against his entrance, but Sans’s wail of pleasure made it worth it. 

Papyrus used the dual action of stretching Sans out and finally giving his neglected cock some light strokes until Sans was torn between thrusting forward or back. In their reflection he could see tears forming in Sans’s sockets from being overwhelmed, the delicious expression pushing Papyrus’s decision to move forward as soon as possible. They had both waited long enough, and Sans was worked up enough for the last part of his plan to work. Papyrus pulled his fingers out, shifting their positions again quickly so his cock was pressing just outside Sans’s entrance. 

“I Love You Sans, All Of You” Papyrus said clearly, not wanting Sans to miss a single word of what he wanted to say. Still he was a little nervous about the next part, he really hoped that it was going to work.  “Look Up, See The Mirror? I Want You To Watch Me Fuck You. I Want You To See What I See” 

Sans gasped and spluttered in surprise as he made eye contact with his reflection, but Papyrus had timed it perfectly with him pressing inside. They both watched Sans’s confused expression slip as he moaned loudly until Papyrus was fully seated inside. They sat there panting for a second, both equally feeling the effects of holding back. But with Sans in his lap with his feet barley touching the floor Papyrus was in full control of everything they did. Sans had trusted him with everything so far, and Papyrus was set on turning that trust into something his brother would never forget. 

Papyrus moved his hands under Sans’s supple thighs so he could lift him up almost completely off his cock before slowly sinking back inside. He repeated this action a few times, growling low in his chest to stop himself from pounding into Sans until they both were seeing stars. Sans’s noises made it more than worth while, he was mewling and arching wantonly at every point of the slow rise and fall. Tears were streaming down his face and his hands were gripping Papyrus almost painfully, but that just made Papyrus need him _more_. 

“Do You Like That Brother?” Papyrus shifted so he could whisper right next to Sans’s skull in a low rumble, the resulting shivers from his brother making it even harder to hold back. But this was all for Sans, Papyrus knew he could do anything if it was for him. “I Want To Make You Feel Good Sans, Tell Me What’s Going To Make You Scream.” 

Sans tore his eyes away from his own reflection to flick his eyes towards Papyrus’s image, panting and writhing all the while. “hnn- fuck- i’m- ah- faster! pap- please, oh gods.”

Papyrus didn’t stop the way his expression turned predatory this time, not while Sans was watching his mirror image so intently. He gave Sans barely any time to prepare before he lifted him up again and started thrusting into his magic properly. Sans’s moans were like music ringing inside his skull, and Papyrus caught himself grinning in their reflection as his plan worked towards a glorious crescendo. With all of the build up he knew that neither of them were going to last much longer, but he needed to stay focused so he could give him the best finish possible. 

Papyrus let his words flow freely, knowing just how much Sans loved to hear how much he was enjoying himself too. “Sans You Feel Amazing, You Look So Good Bouncing In My Lap Like This- I’m- Hah- I’m Getting Close.” 

“pap- ah! paps please i wanna cum, holy shit. this feels so good, i-i can see everything- oh fuck”

Papyrus slammed into Sans harder, losing himself in the moment from his brother’s words and the fact that his plan with the mirror had definitely worked. “Touch Yourself Sans” he growled, his soul pounding when Sans did as he was told immediately. “Watch Yourself Cum All Over Your Hand, Then Watch Me Fill You Up.” 

Sans jerked his cock frantically before arching his spine and bearing down on Papyrus’s cock as hard as he could. “fuck- papyrus!

Liquid magic covered Sans’s hand in spurts as he screamed with an intense climax, the tightening of his magic pushing Papyrus to the edge. He thrust into Sans once more, bottoming out and filling his walls with hot cum. Papyrus moaned in relief as he moved Sans slowly, riding both of their climaxes out as much as possible. When it was over he made sure to set Sans down gently before gathering all the necessary items to clean up. Though it was becoming increasingly difficult to focus when Sans kept chuckling to himself as he basked in the afterglow. 

Even though he knew he was going to regret it immediately, Papyrus took the bait. 

“What Is It Sans?” 

“I know you wanted me to feel good about myself paps” Sans shifted closer to where Papyrus was knelt on the bed with a huge grin on his face. “-but this put a whole new spin on _self reflection_ ”

Papyrus groaned, burying his head in his hands. “You’re Insufferable, You Know That Right?”

“love you too, bro” Sans chuckled softly before his expression shifted into a smile so sincere it made Papyrus’s soul flip, before leaning in and planting a soft kiss on Papyrus’s teeth. “thank you.”


End file.
